Familiarize yourself with the tone of the publication you want to write book reviews for. While all book reviews should contain some of the same elements, publications often present book reviews with varying tones. A serious literary publication may expect your review to focus more on the literary aspects of a book, such as the author's use of symbolism and metaphor, where a publication that reviews horror books may want you to write a plot-oriented review of the book.
Read the book you are going to review and make notes to yourself in a notebook about particular scenes you want to be sure to touch upon in your review. Make notes about important characters and elements of the book you feel are important to share with readers.
Inject the right personality into the review you're writing. Whenever possible, write with a signature style that makes your reviews stand out. You might have a penchant for using humor in your reviews. Your signature may be your outspoken criticism. Develop a style that gives your reviews character. Remember, this may not apply to all publications. If you write book reviews for a literary publication, the publication may prefer book reviews devoid of personality.
Introduce the author of the book, the main characters, the setting and the premise of the book in the first paragraph. Review the plot without giving away anything that will spoil the book for readers. If you need to reveal something that will give away the ending or another important element of the book, give readers a spoiler alert. For serious literary publications, talk about the author's use of metaphor, symbolism and other literary devices used in writing the book.
Finish your review with your opinion of the book overall and your recommendation as to whether or not readers should bother reading it.